Chapter 3 The Biosphere. Section 3-1 What is Ecology?

Chapter 3Chapter 3

The BiosphereThe Biosphere

Section 3-1Section 3-1

What is Ecology?What is Ecology?

Interactions & InterdependenceInteractions & Interdependence

• Ecology –the study of interactions among orgs. & between orgs. & their env., or surroundings.

• The term ecology comes from the Greek word oikos, meaning “house”.

• Our world is a household made of many houses.

• The largest of these houses is the biosphere.

• Biosphere –the part of Earth in which life exists including land, water, & air or the atmosphere.

Levels of OrganizationLevels of Organization

• There are many levels of organization that ecologists study.

• You have:– Species– Population– Community– Ecosystem– Biome– Biosphere

• Species –a group of orgs so similar to one another that they can breed & produce fertile offspring.

• Population –groups of individuals that belong to the same species & live in the same area.

• Communities –groups of different populations that live together in a defined area.

• Ecosystem –a collection of all the orgs. that live in a particular place, together w/ their nonliving or physical, env.

• Teams of ecologists may study larger systems called biomes.

• Biomes –a group of ecosystems that have the same climate & similar dominant communities.

• The highest level of organization that ecologists study is the biosphere.

Ecological MethodsEcological Methods

• Ecologists use a number of tools & techniques to study the living world.

• The 3 basic approaches they use:– Observing (most common in Biology)– Experimenting– Modeling

• Observing– Using your senses to gather data.– Often the 1st step in asking questions.

• Experimenting– Used to test hypothesis.– Can be done in a lab or in the field.

• Modeling– Models help us understand complex events

such as:• Global warming

– Usually consists of mathematical formulas based on data collected through observation & experimentation.

Section 2Section 2

Energy FlowEnergy Flow

ProducersProducers

• Without a constant input of energy, living systems can’t function.

• What is the main source of energy for life on Earth?

The SunThe Sun

• Less than 1% of the sun’s E gets used by living things.

• In a few ecosystems, some orgs. obtain E from a source other than sunlight.– Those orgs. rely on E stored in inorganic

chemical compounds.

• Plants, algae, & certain bacteria capture E from sunlight or chemicals to produce food.– They are called autotrophs.

• Autotrophs –orgs. that capture E from sunlight or chemicals & use it to make their own food from inorganic compounds.– AKA producers.

• Producers:– Can capture E from the sun or chemical

energy.

– Ex:• Plants, algae, some bacteria.• Fig. 3-4

Produce SectionProduce Section

Energy from the SunEnergy from the Sun

• Photosynthesis –process by which plants & some other orgs. use light E to convert H2O & CO2 into O & carbs such as:

– starches & sugars– Fig. 3-2

• This process takes in CO2 & releases O2.

Life W/out LightLife W/out Light

• Some autotrophs can make E w/out sunlight.

• They rely on E held in the chemical bonds found in inorganic molecules.– Ex: hydrogen sulfide

• This process is called chemosynthesis.

Hydrothermal VentHydrothermal Vent

Bacteria living under glaciersBacteria living under glaciers

ConsumersConsumers

• Many orgs. Can’t harness the sun for E.– Ex: animals, fungi, & most bacteria

• The only way these orgs. get E is by eating something.

• These orgs. are called heterotrophs.

• Heterotrophs are consumers.

• There are many different types of consumers:– Herbivores

• Eat only plants• Ex: cows, deer, caterpillars

– Carnivores• Eat other consumers• Ex: snakes, dogs, owls

– Omnivores• Eat both animals & plants• Ex: humans, bears, crows

– Detritivores• Feed on plant & animal remains & other dead matter,

collectively called detritus.• Ex: mites, earthworms, snails, crabs

– Decomposers• Break down organic matter• Ex: bacteria & fungi

Feeding RelationshipsFeeding Relationships

• Food Chains

• Food webs

• Trophic levels

• Food chain –a series of steps in an ecosystem in which orgs. transfer E by eating & being eaten.

Food ChainFood Chain

• Food Web – a network of feeding relationships among the various orgs. in an ecosystem.

Food WebFood Web

• Trophic Level –each step in a food web or food chain.

• Producers make up the 1st level.

• Consumers make up the higher levels.

• Every consumer depends on the trophic level below it for E.

Ecological PyramidsEcological Pyramids

• Ecological pyramid –a diagram that shows the relative amounts of E or matter contained w/in each trophic level.

• 3 types:– E pyramid– Biomass pyramid– Pyramid of numbers

• E pyramid:– Only about 10% of the E available w/in one

trophic level is transferred to orgs in the next level.

– Much E is lost as heat in the env.

• Biomass Pyramid:– Shows the total amount of living tissue w/in a

given trophic level.– Expressed in terms of grams of organic

matter per unit area.– Represents the amount of potential food at

each trophic level.

• Pyramid of Numbers:– Shows us the number of individual orgs at

each trophic level.– P. 73, fig. 3-9

Ecological PyramidsEcological Pyramids

Pyramid of NumbersShows the relativenumber of individualorganisms at eachtrophic level.

Biomass PyramidRepresents the amount ofliving organic matter at each trophic level. Typically, thegreatest biomass is at the base of the pyramid.

Energy PyramidShows the relative amount of energy available at each trophic level. Organisms use about 10 percent of this energy for life processes. The rest is lost as heat.

Section 3Section 3

Cycles of MatterCycles of Matter

CO2 in Ocean

CO2 inAtmosphere

N2 in Atmosphere

NH3

NO3-

and NO2-

Condensation

Seepage

Runoff

Precipitation

TranspirationEvaporation

RootUptake